IMPROVEMENTS OF BCU-BASED DIRECT METHODS AND APPLICATIONS OF BCU TO LINE SWITCHING DESIGNS FOR ENHANCING ONLINE TRANSIENT STABILITY OF LOOK-AHEAD POWER SYSTEMS

The structure, layout, and components of the electric power grid are changing rapidly leading to new components, models, and power system static and dynamic behaviors that existing power system analysis tools cannot accommodate. Since electricity is an integral part of our daily lives, it is important that power system analysis and control tools keep up with the changes in the power grid. An existing methodology/tool with the potential to help the power industry keep up with the changing needs for dynamic stability and control of the power system, due to its strong theoretical basis, is the boundary of the stability region based controlling unstable equilibrium point (BCU) method. This thesis develops tools for the online transient stability analysis and control of modern power systems using the BCU method. Towards this goal we first propose a method for improving the robustness of unstable equilibrium point computations using a combination of quotient gradient transformation and the pseudo-transient continuation method. We also extend the application of the BCU method to the assessment of the transient stability of power systems with nonlinear excitation system models. The thesis also studies the dynamics of transmission line switching events under changing loading conditions and proposes and implements a novel BCU-based method for the direct transient stability assessment of transmission switching events. A method based on a three-stage strategy is also proposed for the fast determination of transmission line switching candidates that can be used to enhance the transient stability of multiple contingencies for look-ahead loading conditions of a power system. Finally, a three-stage, fast scenario-based tool for the online transient stability assessments of power systems with load or generation uncertainties under look-ahead load conditions is proposed and implemented